138604221 has 24 divisors (see below), whose sum is σ = 240851520. Its totient is φ = 75033216.

The previous prime is 138604211. The next prime is 138604237. The reversal of 138604221 is 122406831.

138604221 is a `hidden beast` number, since 1 + 38 + 604 + 2 + 21 = 666.

It is not a de Polignac number, because 138604221 - 2⁹ = 138603709 is a prime.

It is a super-2 number, since 2×138604221² = 38422260158033682, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138604211) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 56700 + ... + 59093.

It is an arithmetic number, because the mean of its divisors is an integer number (10035480).

Almost surely, 2^138604221 is an apocalyptic number.

It is an amenable number.

138604221 is a deficient number, since it is larger than the sum of its proper divisors (102247299).

138604221 is a wasteful number, since it uses less digits than its factorization.

138604221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 115825 (or 115822 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 138604221 is about 11773.0293892439. The cubic root of 138604221 is about 517.5180305977.

It can be divided in two parts, 13860 and 4221, that added together give a palindrome (18081).

The spelling of 138604221 in words is "one hundred thirty-eight million, six hundred four thousand, two hundred twenty-one".